1. Field of the Invention
The present invention relates to a floppy disk drive, and particularly to an improved drive for a micro-floppy disk cartridge which contains a floppy disk as an information recording medium.
2. Prior Art
There are known various information recording media used as external memories for computers. Among them, magnetic disks are currently utilized since they are randomly accessible and easily handled. Recently, a so-called floppy disk has been developed which includes a substrate of flexible plastic sheet having one or two faces coated with magnetically storing layers. The floppy disk is increasingly used over the broad range of applications since it has many advantages, for example, in that the floppy disk is cheaper than hard disks and in that the floppy disk can easily be changed to another floppy disk to increase the capacity of memory.
More recently, a so-called cartridge type micro-floppy disk has been developed in which a floppy disk as an information recording medium is contained within a cartridge of hard plastic casing or the like. This is advantageous in that the floppy disk can extremely easily and simply be carried and handled while preventing the recording face(s) thereof from being damaged and contaminated by any foreign matters. Such a micro-floppy disk cartridge is broadly being utilized as an excellent external memory in small-size computers and particularly personal and domestic computers.
In the micro-floppy disk cartridge, the micro-floppy disk is housed within a hard plastic casing which has a shutter mechanism for preventing the READ/WRITE faces of the disk from being exposed to protect the recording faces substantially completely from any foreign matters. Thus, a user can handle the floppy disk without his additional attention to the damage and contamination of the recording faces in the floppy disk. The micro-floppy disk cartridge also is mailable.
In order to most utilize the advantages of the micro-floppy disk cartridge, a floppy disk drive therefor must have various new performances different from those of the conventional 8-inch floppy disk drive. Main requirements to the micro-floppy disk drive is that it can be reduced in size and can be operated with the minimum power consumption.
Computers themselves are remarkably being reduced in size while increasing their processing speed and capacity. It is thus known that the entire size of a computer system depends on the dimension and arrangement of a keyboard, monitor and external memory. Consequently, the micro-floppy disk drive should necessarily be reduced in size and operated with the minimum power consumption such that a portable microcomputer can be realized.
The conventional micro-floppy disk drives comprise mechanisms similar to those of large-sized floppy disk drives. In most of the conventional micro-floppy disk drives, the disk is loaded into the forward loading port of the drive (front loading). In such a construction, the drive must have a passage for the cartridge. This provides a limitation when the size of the drive should be decreased, particularly to obtain a portable type floppy disk drive having a reduced thickness.
Since the floppy disk generally has the opposite WRITE faces, the drive must have two drive heads adapted to contact the opposite faces of the disk.
In such a double-headed floppy disk drive, however, the heads must accurately be positioned relative to each other. If the relative position between two heads is not proper, the READ/WRITE cannot be effected. In general, each of the heads is carried by a carriage or arm and must travel over all the trucks of floppy disk. Therefore, a simple mechanism for adjusting the relative position between the heads which can be assembled into the drive is eagerly desired in the art.
In the micro-floppy disk drive, the disk is adapted to be held between the heads under pressure. The heads are biased toward each other under pressure also when no cartridge is loaded therebetween. This results in damage of the heads.